Recent Developments in Cavitation Mechanisms (eBook)

A Guide for Scientists and Engineers

Seiichi Washio (Autor)

eBook Download: PDF | EPUB

2014 | 1. Auflage
288 Seiten
Elsevier Science (Verlag)
978-1-78242-176-4 (ISBN)

Infos

How does cavitation start? Presently, the nucleus theory provides the answer to this fundamental question. However the idea of nuclei contains inaccuracies that cannot be rationalized. Recent Developments in Cavitation Mechanisms discusses the uncertainties surrounding the nucleus theory, and proposes another theory of cavitation mechanism. Characteristically, the new theory is based on recent discoveries of cavity generation phenomena in separating flows. This book consists of chapters that introduce topics such as unsoundness of cavitation nuclei, and phenomena of cavity generation on walls of flow separation in hydraulic oil and water flows. Subsequent chapters cover the mechanism of cavity generation at point of flow separation, nucleation by contact motion between solids in liquid and a proposal of new cavitation mechanism based on flow separation and solid contact. The final chapters present the demonstration of a new mechanism in the hydraulic poppet valve and a concluding summary. - proposes a new mechanism of cavitation inception in liquid machines - describes in detail phenomena of cavity generation at point of flow separation recently discovered by the author - discusses peculiar properties of flow separation as cause of cavity generation - presents abundant experimental data of incipient cavitation obtained with high resolution of time and space - provides supplementary materials of slow motion videos that can help understand the very rapid and minute phenomena of cavity generation which has been discovered by the author and will be still unfamiliar to many

Seichi Washio is an emeritus professor of Okayama University, Okayama, Japan.

Inhalt

Cover 
1 
Recent developments in cavitation mechanisms: A guide for scientists and engineers 
4 
Copyright 
5 
Contents 6
List of figures and tables 
10 
Figures 10
Tables 23
Preface 24
Acknowledgements 28
About the author 30
1 Review of cavitation nuclei 
32 
1.1 Traditional pictures of nuclei 32
1.2 Nuclei in hydraulic mineral oil 34
1.3 Unsoundness of traditional nuclei models 53
1.4 Tribonucleation 60
1.5 Appendix I: Saturated solubility, diffusion coefficient and surface tension 
61 
1.6 Appendix II: Effects of bubble on transient wave 72
1.7 References 73
2 Experimental methods 
76 
2.1 Preliminary remarks 76
2.2 Microscope 77
2.3 Photography 78
2.4 Laser beam transmission 79
2.5 Measurements of physical quantities 80
2.6 Flows and channels 81
2.7 Observation of tribonucleation 82
2.8 References 82
3 Cavitation inception in separating oil flows 
84 
3.1 Test channels for observation of cavitation 84
3.2 Experimental parameters 88
3.3 Oil flows with separation and reattachment in two-dimensional constriction 
89 
3.4 Oil flows separating at a tip of needle projection 
119 
3.5 Oil flows separating from smooth surface 
135 
3.6 Summary 160
3.7 References 161
4 Cavitation inception in separating water flows 
164 
4.1 Experimental apparatus 164
4.2 Cavity generation and cavitation in separating water flows 
167 
4.3 Pressure dependence of cavity generation 178
4.4 Choking of water fl ow in 2-D constriction 181
4.5 Summary 187
4.6 References 188
5 Singular properties of flow separation as a cause of cavitation inception 
190 
5.1 Tensions at point of flow separation 
190 
5.2 Heat generation at point of separation 198
5.3 PIV inspection of separation flow 
202 
5.4 Mechanism of tension and heat generations by flow separation 
206 
5.5 Hypothesis of cavity generation mechanism at point of flow separation 
210 
5.6 References 213
6 Tribonucleation by contact motion between solids in liquid 
216 
6.1 Tribonucleation 216
6.2 Nucleation by separation of solid walls in liquid 218
6.3 Nucleation by sliding motion between surfaces contacting in liquid 235
6.4 Summary 245
6.5 References 246
7 Cavity generation by flow separation and solid contact in a hydraulic poppet valve 
248 
7.1 Preliminary remarks 248
7.2 Experimental setup 249
7.3 Cavitation in a poppet valve with fixed clearance 
254 
7.4 Cavitation in a poppet valve with variable clearance 268
7.5 Summary 280
7.6 Reference 281
Afterword 282
Index 284

Produkt-Details

• Erscheint lt. Verlag: 28.8.2014
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Chemie ► Technische Chemie
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Strömungsmechanik
• Themenwelt: Technik ► Maschinenbau
• Themenwelt: Technik ► Umwelttechnik / Biotechnologie
• ISBN-10: 1-78242-176-9 / 1782421769
• ISBN-13: 978-1-78242-176-4 / 9781782421764